Abrasive wear from the outer race creeping, or actual distortion of the casing John? If the latter, hopefully there is enough material to support a sleeve without the problem becoming more severe.
Been reading John's log on restoring Double Trouble. Ran across an article about a couple of other multiengine restorations being done. https://www.dragbike.com/collins-cooper-past-becoming-future/?fbclid=IwAR3muZ1sJGVVZzC3-p2tdBrKfPfXujfwgW67wa3VnDH3PVLhOl-2b5sTAyg RC engineering, Atchison, Topeka,...
As George puts it "sometimes CAD (cardboard aided design) works out well. Have tried it using paper towel tubes for exhaust stand in. Works if you don't have to bend them.
Unfortunately, most of my projects at the moment involve tractors and mowing equipment. Need to get more time with my toys and less fixing trail problems.